This invention relates generally to machine tools, and more paritcularly to a shearing machine wherein cuts are made simultaneously on intersecting lines to produce a finished blank from a sheet positioned and held by power driven means and a numerically controlled feeding device.
It is quite common for the shear operator to line up metal sheets in a working position either by hand or by means of feeding devices in the course of which the sheets are moved against adjustable end stops.
In addition to conventional well known and widely used shears, there are patents referring to apparatus for cutting sheet metal into blanks along a pre-determined line by means of a shear with two cutting edges which are located at right angles to one another. In this apparatus, the sheet is arranged on a carriage that can be moved in two directions and held on the edge opposite to the shear by two clamps. The sheet is then positioned relative to the two cutting edges intersecting at right angles in such a way that only the piece to be cut off is located in the enclosed space formed by the cutting edges, whereas the remainder of the metal sheet is outside this space. This system has a large floor-space requirement and precludes the possibility of stacking the various pieces of cut sheet metal individually. In addition, it is not possible to trim a sheet on all four sides to "square it up".
Although the aforementioned patents deal with various methods and forms of apparatus for cutting metal materials, none of them is intended for shearing blanks of assorted sizes from sheet metal material. There remains a need for equipment capable of economically and accurately shearing sheet metal material into finished blanks of desired sizes.